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A better understanding of the impacts of environmental drivers on the population dynamics and abundance of key fishery species can inform flexible management decisions that pre-empt both risks of overfishing under adverse environmental conditions and opportunities for increased harvest under favourable conditions. This is increasingly important as shifting environmental dynamics drive geographical shifts in fish stocks.

This project will identify environmental variables influencing the abundance of three priority fishery species, quantify those relationships to enhance their stock assessment models, and develop a forward projection tool to inform adaptive management of each fishery. Target species - Spanner Crabs, Snapper and Pearl Perch – were selected based on key interest to management of fisheries in Queensland and NSW. Some associations between these species and certain abiotic environmental factors are already known, but there is yet to be a rigorous and comprehensive approach to this work, with the explicit goal of incorporating abiotic influences into Queensland and NSW stock assessments.

The project has three key objectives: (1) Find indices of association between measures of abundance and key environmental drivers; (2) Use these indices to enhance the existing stock assessment model for each species; and (3) Enable forecasting of environmentally driven fluctuations in targeted species’ abundance, including enhancing Management Strategy Evaluations (MSEs).

In particular, environmental correlates will be valuable to fisheries managers by: (a) reducing the uncertainty in biomass estimates, (b) explaining fluctuations in abundance, and (c) characterising what is a “bad year” for each species. Such information can be incorporated into MSEs.

The “Queensland Sustainable Fisheries Strategy 2017-2027” identifies several challenges to fulfilling its mission of ensuring the sustainability of fisheries and the economic viability of fishing sectors. The first of these is “gaps in monitoring and research, which limit the ability to make timely, evidence-based decisions”. This project will close some of these gaps and assist in formulating measures for promoting stock recovery and adaptive management.

Objectives

1. Find indices of association between measures of abundance and environmental drivers.

2. Improve stock assessment models, for targeted species, by incorporating environmental drivers.

3. Enable forecasting of environmentally driven fluctuations in species’ abundance, including enhancing Management Strategy Evaluations for targeted species with the help of a rapid adaptive projections tool (RAPT).

Final report

ISBN: 978-1-74272-356-3

Authors: J. A. Filar A.J. Courtney L. J. Gibson R. Jemison S. Leahy Y. Lei M. Mendiolar J. Mitchell B. Robson C. Steinberg S. Williams W.-H. Yang N. Ye.

Final Report • 2021-12-31 • 12.89 MB

2019-013-DLD.pdf

Summary

This project studied environmental factors which may be influencing the recruitment, catchability or productivity of Snapper, Pearl Perch, and Spanner Crab stocks in Queensland. Two environmental variables: GSLA and Chl-a were found to have strong associations with either abundance or catchability across the three target species. These associations occurred at spatio-temporal scales relevant to each species’ biology. A third variable, SST, also had strong associations with Snapper.

Importantly, all three of these environment variables, GSLA, SST and Chl-a were found to have certain consistent long-term trends, with rates of change depending somewhat on the region under consideration. We demonstrated that incorporating these environmental variables into simple surplus production stock assessment models results, under some scenarios, in delays in stock recovery. This assumed that the above trends of GSLA, SST and Chl-a are sustained and the direction and strength of the identified associations are maintained.

Assessing the spawning characteristics and reproductive biology of Pearl Perch (Glaucosoma scapulare) in Queensland

Project number: 2018-074

Project Status:

Completed

Budget expenditure: $376,154.78

Principal Investigator: Matthew J. Campbell

Organisation: Department of Primary Industries (QLD)

Project start/end date: 31 Mar 2019 - 30 Dec 2021

Contact:

FRDC

TAGS

SPECIES

Need

This project addresses the national research priority "Ensuring that Australian fishing and aquaculture products are sustainable and acknowledged to be so", identified by FRDC as part of their RD&E Plan for the period 2015-2020. Further, this project addresses a research priority listed in FRDC's April 2018 Competitive round call for Expressions of Interest "To gain a better understanding of the spawning aggregations and dynamics of pearl perch". This project also addresses a Fisheries Queensland’s priority identified in their 2017 Monitoring and Research Plan "Research into lifecycle characteristics of pearl perch".

Outputs from a recent stock assessment suggested that the pearl perch stock, which extends southwards into New South Wales waters, is transitional depleted and stock recovery is necessary. This requires an improvement in egg production achievable through the protection of spawning animals. Knowledge of the pearl perch’s spawning dynamics would enable fishery managers to make evidence-based decisions regarding the harvest strategies that increase egg production and, therefore, build the stock biomass. For example, should patterns of pearl perch spawning aggregations be located, like those of the confamilial West Australian dhufish (belonging to the same taxonomic fish family), spatial closures could be employed to protect these aggregations. Similarly, temporal closures are currently used to avoid excessive fishing mortality on coral trout spawning aggregations and similar protection for pearl perch may be appropriate if spawning is timed to coincide with certain biological or seasonal cues. A thorough understanding of these spawning dynamics of the pearl perch is necessary to inform management of the species.

There is a need, therefore, to: (1) collect relevant biological information pertaining to the spawning dynamics of pearl perch, (2) supplement current information with fishery-independent data to better define temporal and spatial spawning patterns over the entire extent of the species’ distribution, and (3) identify areas likely to support spawning aggregations, if any, and to assess the movement to and from these spawning aggregations.

Objectives

1. Assess the temporal and spatial trends in the reproductive biology of pearl perch

2. Determine the movement of spawning pearl perch using both conventional and acoustic tagging methods

3. Identify areas, if any, that support spawning aggregations and determine the relative importance of these aggregations to the sustainability of the pearl perch stock